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Biomedical subjects

M Gao

Publications and source records attributed to M Gao.

At least 163 records · Page 9Linked to original sources
PubMed1996

The imbalance of plasminogen activators and inhibitor in preeclampsia.

OBJECTIVE: To evaluate the role of plasminogen activators (tPA uPA) and inhibitor (PAI-1) in the pathogenesis of preeclampsia. STUDY DESIGN: tPA uPA and PAI-1 antigens were measured in amniotic fluid, maternal plasma, and placental homogenates in normal pregnancy by ELISA method and compared with that of preeclampsia. RESULTS: In normal pregnancy, tPA, uPA and PAI-1 levels increase as the gestation advance, but the increment of PAI-1 in amniotic fluid (28.3-fold) is larger than that of tPA and uPA (1.8-fold, 8.5-fold) (p < 0.001). Decidua homogenates contained larger amount of PAI-1 than villi. Whereas, villi had higher levels of tPA uPA than decidua (p < 0.01). In preeclampsia, the significantly higher levels of PAI-1 were observed in AF and decidua tissue as compared to the normals (p < 0.01), and the increment of PAI-1 in preeclampsia is larger than that of tPA, uPA. CONCLUSIONS: The elevated PAI-1 level is associated with the preeclampsia and the imbalance between the plasminogen activators (tPA, uPA) and the inhibitor (PAI-1) might be involved in the pathogenesis of preeclampsia.

Amniotic Fluid↗
PubMed1996

Separate functional domains of the herpes simplex virus type 1 protease: evidence for cleavage inside capsids.

The herpes simplex virus type 1 (HSV-1) protease (Pra) and related proteins are involved in the assembly of viral capsids and virion maturation. Pra is a serine protease, and the active-site residue has been mapped to amino acid (aa) 129 (Ser). This 635-aa protease, encoded by the UL26 gene, is autoproteolytically processed at two sites, the release (R) site between amino acid residues 247 and 248 and the maturation (M) site between residues 610 and 611. When the protease cleaves itself at both sites, it releases Nb, the catalytic domain (N0), and the C-terminal 25 aa. ICP35, a substrate of the HSV-1 protease, is the product of the UL26.5 gene. As it is translated from a Met codon within the UL26 gene, ICP35 cd are identical to the C-terminal 329-aa sequence of the protease and are trans cleaved at an identical C-terminal site to generate ICP35 e,f and a 25-aa peptide. Only fully processed Pra (N0 and Nb) and ICP35 (ICP35 e,f) are present in B capsids, which are believed to be precursors of mature virions. Using an R-site mutant A247S virus, we have recently shown that this mutant protease retains enzymatic activity but fails to support viral growth, suggesting that the release of N0 is required for viral replication. Here we report that another mutant protease, with an amino acid substitution (Ser to Cys) at the active site, can complement the A247S mutant but not a protease deletion mutant. Cell lines expressing the active-site mutant protease were isolated and shown to complement the A247S mutant at the levels of capsid assembly, DNA packaging, and viral growth. Therefore, the complementation between the R-site mutant and the active-site mutant reconstituted wild-type Pra function. One feature of this intragenic complementation is that following sedimentation of infected-cell lysates on sucrose gradients, both N-terminally unprocessed and processed proteases were isolated from the fractions where normal B capsids sediment, suggesting that proteolytic processing occurs inside capsids. Our results demonstrate that the HSV-1 protease has distinct functional domains and some of these functions can complement in trans.

Animals↗
PubMed1996

[A pilot study on trihalomethane formation in water treated by chlorine dioxide].

Trihalomethane (THM) formation was determined by gas chromatography in water disinfected with chlorine dioxide (ClO2) only or ClO2 combined with chlorine (Cl2), to lay a basis for water disinfected with ClO2. Results showed no THM was produced in water disinfected with ClO2 only if without existence of bromine (Br) ion in it; certain amount of bromoform could be formed with existence of bromine ion, and THM formation could be inhibited by ClO2 and Cl2, with a ratio of greater than 1 between them. Light irradiation could decrease the amount of THM produced whether in disinfection with ClO2 or combination with ClO2 and Cl2. No significant effect of pH value of water on THM formation was observed, but pH should be controlled under neutral or slightly acidic to ensure the concentration of ClO2 in water.

Carcinogens↗
PubMed1996

Neutralization of human immunodeficiency virus type 1 (HIV-1) with antibody from carriers' plasma against HIV-1 protein p17.

It was investigated whether human antibody against HIV-1 protein p17 (anti-p17) in HIV carriers' plasma has the ability to neutralize the infectivity of HIV. By the pretreatment of HIV-1 with anti-p17 from HIV carriers, progeny HIV-1 production from cells infected with virus pretreated with anti-p17 was suppressed and/or delayed. The neutralizing activity of anti-p17 was decreased in the presence of recombinant p17. The latter obviously masked the neutralizing activity of anti-p17. The relevant epitope(s) on p17 is located apparently on the surface of HIV virions and the binding of anti-p17 to p17 impairs the infectivity of HIV. This implies that anti-p17, if stably present in HIV carriers' plasma, may also play an important role in reducing the infectivity of HIV-1 in vivo.

Antibody Specificity↗
PubMed1996

[Increase of mu opioid receptor density in rat central nervous system following formalin nociception and its enhancement by electroacupuncture].

Using receptor autoradiography it was found: (1) After formalin injection in the rat hind paw, the mu opioid receptor density was significantly increased in certain central areas related to antinociception, i.e., the caudate nucleus, nucleus accumbens, amygdaloid nucleus, periaqueductal gray, interpeduncular nucleus, nucleus raphe magnus and spinal dorsal horn. (2) In addition to most of above mentioned central areas, in rat whose noxious responses were inhibited by electroacupuncture, there was a significant increase of receptor density in the cingulate cortex, septal area, preoptic area, superior central nucleus, superior colliculus and medial geniculate body. In comparison with the rats with formalin injection alone, the receptor density in the interpeduncular nucleus, the ventrolateral part of the caudal periaqueductal gray and spinal dorsal horn of the lumbar enlargement was further increased in the rats showing electroacupuncture analgesia. The above results provide further evidence supporting the postulation that noxious stimulation is capable of activating endogenous opioid peptidergic system which is further enhanced by electroacupuncture.

Acupuncture Analgesia↗
PubMed1996

[Distribution of Bacillus thuringiensis in soils of north and south of China].

221 isolates of Bacillus thuringiensis were isolated in 1491 soil samples from North and South of China. H-serotypes and larvicidal characters of all Bt isolates have been identified. The rate of Bt-harbouring soil sample and the rate of Bt isolates in Northeast and Neimeng were in 12.6% and 17.2% respectively. Predominant serotypes were H4, H10, H3, H13, H5 and H29. The most fertile Bt-harbouring area was the Heilongjiang Province with rate of Bt-harbouring sample of 21.4% and rate of Bt isolate of 29.4%. Rate of Bt-harbouring sample and rate of Bt isolate in Northwest area were 6.6% and 7.1% respectively. Main serotypes were H4, H5, H19, H10 and H3. In four provinces of Southern China, both rates above were 18.6% and 29.5%, but frequency of Bt distribution was varied seriously in different distinct. Predominant serotypes in soils from Southern China were H3 and H5. Results of bioassay showed that the percentage of strains high active to Heliothis armigera and Plogioidera versicolora were 1.6% and 1.1% in soils from North of China. In contrast to North of China, Bt strains active to H. armigera were 5.3% and none of Bt was effective to P. versicolora in South of China. A strain H27-05 was high toxic to H. armigera and showed temperate toxicity to P. versicolora.

Animals↗
PubMed1996

[Outpatient treatment of obstructive sleep apnea syndrome with CO2 laser: laser-assisted uvulopalatoplasty].

To find a safe and convenient method for the treatment of obstructive sleep apnea syndrome, 89 outpatient cases were treated with CO2 laser-assisted uvulopalatoplasty. All cases had been diagnosed and observed with polysomnographic monitoring. The result of 89 cases of OSAS was judged as good in 67 cases (75.7%). Only 6 cases had a little bleeding during operation, no other complication has been encountered.

Adult↗
PubMed1995

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Journal Article↗
PubMed1995

Multiple protein-DNA interactions over the yeast HSC82 heat shock gene promoter.

We have utilized DNase I and micrococcal nuclease (MNase) to map the chromatin structure of the HSC82 heat shock gene of Saccharomyces cerevisiae. The gene is expressed at a high basal level which is enhanced 2-3-fold by thermal stress. A single, heat-shock invariant DNase I hypersensitive domain is found within the HSC82 chromosomal locus; it maps to the gene's 5' end and spans 250 bp of promoter sequence. DNase I genomic footprinting reveals that within this hypersensitive region are four constitutive protein-DNA interactions. These map to the transcription initiation site, the TATA box, the promoter-distal heat shock element (HSE1) and a consensus GRF2 (REB1/Factor Y) sequence. However, two other potential regulatory sites, the promoter-proximal heat shock element (HSE0) and a consensus upstream repressor sequence (URS1), are not detectably occupied under either transcriptional state. In contrast to its sensitivity to DNAase I, the nucleosome-free promoter region is relatively protected from MNase; the enzyme excises a stable nucleoprotein fragment of approximately 210 bp. As detected by MNase, there are at least two sequence-positioned nucleosomes arrayed 5' of the promoter; regularly spaced nucleosomes exhibiting an average repeat length of 160-170 bp span several kilobases of both upstream and downstream regions. Similarly, the body of the gene, which exhibits heightened sensitivity to DNase I, displays a nucleosomal organization under both basal and induced states, but these nucleosomes are not detectably positioned with respect to the underlying DNA sequence and may be irregularly spaced and/or structurally altered. We present a model of the chromatin structure of HSC82 and compare it to one previously derived for the closely related, but differentially regulated, HSP82 heat shock gene.

Base Sequence↗
PubMed1995

Release of the catalytic domain N(o) from the herpes simplex virus type 1 protease is required for viral growth.

The herpes simplex virus type 1 (HSV-1) protease and its substrate, ICP35, are involved in the assembly of viral capsids and required for efficient viral growth. The full-length protease (Pra) consists of 635 amino acid (aa) residues and is autoproteolytically processed at the release (R) site and the maturation (M) site, releasing the catalytic domain No (VP24), Nb (VP21), and a 25-aa peptide. To understand the biological importance of cleavage at these sites, we constructed several mutations in the cloned protease gene. Transfection assays were performed to determine the functional properties of these mutant proteins by their abilities to complement the growth of the protease deletion mutant m100. Our results indicate that (i) expression of full-length protease is not required for viral replication, since a 514-aa protease molecule lacking the M site could support viral growth; and that (ii) elimination of the R site by changing the residue Ala-247 to Ser abolished viral replication. To better understand the functions that are mediated by proteolytic processing at the R site of the protease, we engineered an HSV-1 recombinant virus containing a mutation at this site. Analysis of the mutant A247S virus demonstrated that (i) the mutant protease retained the ability to cleave at the M site and to trans process ICP35 but failed to support viral growth on Vero cells, demonstrating that release of the catalytic domain No from Pra is required for viral replication; and that (ii) only empty capsid structures were observed by electron microscopy in thin sections of A247S-infected Vero cells, indicating that viral DNA was not encapsidated. Our results demonstrate that processing of ICP35 is not sufficient to support viral replication and provide genetic evidence that the HSV-1 protease has nuclear functions other than enzymatic activity.

Amino Acid Sequence↗